diff --unified --recursive --text jbig2enc-0.29/configure.ac jbig2enc-master/configure.ac
--- jbig2enc-0.29/configure.ac	2017-01-30 12:27:36.000000000 -0500
+++ jbig2enc-master/configure.ac	2023-07-11 20:49:46.508050549 -0400
@@ -73,7 +73,7 @@
 	fi],
 [libtool_patch_use_rpath=$enable_rpath])
 
-AC_CHECK_LIB([lept], [findFileFormatStream], [], [
+AC_CHECK_LIB([leptonica], [findFileFormatStream], [], [
 			echo "Error! Leptonica not detected."
 			exit -1
 			])
Only in jbig2enc-master: .git
diff --unified --recursive --text jbig2enc-0.29/src/jbig2.cc jbig2enc-master/src/jbig2.cc
--- jbig2enc-0.29/src/jbig2.cc	2017-01-30 12:27:36.000000000 -0500
+++ jbig2enc-master/src/jbig2.cc	2023-07-11 20:49:46.514717176 -0400
@@ -29,6 +29,9 @@
 #endif
 
 #include <leptonica/allheaders.h>
+#if (LIBLEPT_MAJOR_VERSION == 1 && LIBLEPT_MINOR_VERSION >= 83) || LIBLEPT_MAJOR_VERSION > 1
+#include "leptonica/pix_internal.h"
+#endif
 
 #include "jbig2enc.h"
 
@@ -418,8 +421,11 @@
       if (pixl->d > 8) {
         gray = pixConvertRGBToGrayFast(pixl);
         if (!gray) return 1;
-      } else {
+      } else if (pixl->d == 4 || pixl->d == 8) {
         gray = pixClone(pixl);
+      } else {
+        fprintf(stderr, "Unsupported input image depth: %d\n", pixl->d);
+        return 1;
       }
       if (up2) {
         pixt = pixScaleGray2xLIThresh(gray, bw_threshold);
@@ -432,6 +438,10 @@
     } else {
       pixt = pixClone(pixl);
     }
+    if (!pixt) {
+      fprintf(stderr, "Failed to convert input image to binary\n");
+      return 1;
+    }
     if (verbose)
       pixInfo(pixt, "thresholded image:");
 
diff --unified --recursive --text jbig2enc-0.29/src/jbig2enc.cc jbig2enc-master/src/jbig2enc.cc
--- jbig2enc-0.29/src/jbig2enc.cc	2017-01-30 12:27:36.000000000 -0500
+++ jbig2enc-master/src/jbig2enc.cc	2023-07-11 20:49:46.514717176 -0400
@@ -24,6 +24,10 @@
 #include <string.h>
 
 #include <leptonica/allheaders.h>
+#if (LIBLEPT_MAJOR_VERSION == 1 && LIBLEPT_MINOR_VERSION >= 83) || LIBLEPT_MAJOR_VERSION > 1
+#include "leptonica/pix_internal.h"
+#include "leptonica/array_internal.h"
+#endif
 
 #include <math.h>
 #if defined(sun)
@@ -206,7 +210,11 @@
         numaSetValue(ctx->classer->naclass, i, new_representant);
       }
     }
+#if (LIBLEPT_MAJOR_VERSION == 1 && LIBLEPT_MINOR_VERSION >= 83) || LIBLEPT_MAJOR_VERSION > 1
+    ctx->classer->pixat->pix[new_representant]->refcount += ctx->classer->pixat->pix[second_template]->refcount;
+#else
     pixChangeRefcount(ctx->classer->pixat->pix[new_representant],pixGetRefcount(ctx->classer->pixat->pix[second_template]));
+#endif
   }
   return 0;
 }
diff --unified --recursive --text jbig2enc-0.29/src/jbig2sym.cc jbig2enc-master/src/jbig2sym.cc
--- jbig2enc-0.29/src/jbig2sym.cc	2017-01-30 12:27:36.000000000 -0500
+++ jbig2enc-master/src/jbig2sym.cc	2023-07-11 20:49:46.514717176 -0400
@@ -29,6 +29,10 @@
 #include <stdio.h>
 
 #include <leptonica/allheaders.h>
+#if (LIBLEPT_MAJOR_VERSION == 1 && LIBLEPT_MINOR_VERSION >= 83) || LIBLEPT_MAJOR_VERSION > 1
+#include "leptonica/pix_internal.h"
+#include "leptonica/array_internal.h"
+#endif
 
 #include <math.h>